Switch mechanism



Jan. 5, 1943. G. H. HANSEN 2,307,255

l SWITCH MEGHANISM Filed Sept. 25, 1941 Y f4/Miam Trae/VEKS.

Patented Jan. 5, 1943 SWITCH MECHANISM Gilbert H. Hansen, Batavia, M. Furnas and William C. ing business as Furnas Batavia, Ill.

Ill., assignor to Leto Furnas, partners, do-

Electric Company,

Application September 25, 1941, Serial No. 412,213

16 Claims.

The present invention relates in general to improvements in electric switch mechanisms, and relates more particularly to improvements in the construction and operation of fluid pressure actuated switch assemblages of the type shown and described in Furnas and Hansen Patent No.

coacts with one of the toggle levers through a' disk engaging the top of the Vdiaphragm and having opposite integral side projections provided with knife edges engageable with V-shaped sockets in the opposite side portions of the toggle lever, and the side projections of the disk are normally maintained in snug coaction with the toggle lever sockets by means of a helical spiral spring located within the fluid pressure chamber and coacting with the lower face of the diaphragm. While this spring operates in a satisfactory manner when properly installed and the switch assembly is disposed in normal vertical position, it is relatively costly, rather diicult to install and to retain in proper position, and may permit the intervening disk to become displaced with respect to the diaphragm and lever sockets when the switch is disposed horizontally, thereby making the use of such springs quite objectionable under certain conditions of operation.

It is therefore a more specific object of the present invention to provide improved instrumentalities for maintaining the motion transmitting element or saddle disk of such a pressure actuated switch in proper position with respect to the toggle mechanism which actuates the switch contacts, at all times.

Another specific object of the invention is to provide an improved switch mechanism in which the motion transfer element between the diaphragm and the toggle or switch contacts, is resiliently and effectively maintained in operative position at all times.

A further speci'c object of this invention is to provide a simple and durable pressure switch assembly wherein a relatively loose saddle member or motion transfer disk is interposed between the pressure actuated diaphragm and the contact actuating toggle, and is constantly retained in snug and proper coaction with the toggle lever sockets, by means disposed outside of the fluid chamber.

Still another specific object of the present invention is to provide an improved electric switch structure which can be readily assembled and dismantled, and which may also be manufactured and sold at moderate cost.

An additional specific object of the invention is to provide an improved motion transmitting connection between a fluid actuated diaphragm and a motion transfer lever, which will retain the parts in operative relationship regardless of the disposition of the mechanism.

These and other objects and advantages of the invention will be apparent from the following detailed description.

A clear conception of the features constituting the present improvement, and of the construction and operation of a pressure switch built in accordance with the invention, may be had by referring to the drawing accompanying and 'forming a part of this specification in which like reference characters designate the same or similar parts in the several views.

Fig. 1 is a vertical section through one of the improved fluid pressure actuated switches, showing the same released for automatic pressure actuation and with the contacts opened by fluid pressure;

Fig. 2 is a similar section through the same switch mechanism, showing the contacts closed;

Fig. 3 is a rear side elevation of the same switch assemblage, showing the contact actuating toggles locked in Contact open position by the manually actuated cam;

Fig. 4 is a perspective view of the motion transmitting saddle element which is interposed between the diaphragm and toggle mechanism, and of the leaf spring for holding this element in the lever sockets; and

Fig, 5 is a perspective view of the improved assembly plate for holding the toggle and frame in assembled condition.

While the invention has been shown and described as being especially applicable to a uid pressure actuated electric switch assembly such as disclosed in prior Patent No. 2,193,127, it is not the desire or intent to thereby unnecessarily restrict the scope or utility of the improvement.

With reference to the drawing, the improved fluid pressure actuated electric switch mechanism shown therein, comprises in general, a main frame having a lower base I0 rigidly attached to an upper frame member` II provided with integral lower side walls I2 and upper side flanges |3, and with an integral front wall I4 spanning the space between and extending upwardly above the side walls I2; a lower cup-shaped casing I5 with the bottom of which the frame base i5 coacts, and which is provided with a large central opening I6; a circular exible diaphragm I1 coacting with the lower face of the casing I5 and normally closing the opening I6; a uid pressure tting I8 having a iiange i3 which is clamped against the diaphragm I1 and to the casing I5 and base I5 by means of screws 26 so as to form a fluid chamber 2|; an inverted conical member 22 having a restricted central fluid inlet opening, and being interposed between the chamber 2| and the uid supply; a motion transmitting saddle element or disk 23 coacting with the central top portion of the diaphragm I1 and having integral opposite side projections 24 extending upwardly through the opening I6 and through a hole in the base IB adjacent to the side walls I2; a leaf spring 25 secured to the central upper portion of the disk 23 and extending toward the rear of the switch assemblage; a main U-shaped toggle member or lever 25 having opposite side arms 21 providedwith V-notches 28 which are normally engaged by knife edges at the upper ends of the disk projections 24, the lever 26 being swingable in fulcrum notches 26 formed in the front portions of the frame side walls I2; a primary adjustment spring 36 coacting with the rear swinging portion of the lever 26 and reacting against a cup-washer 3| which coacts with a nut 32 having screw thread coaction with a iixed bolt 33 the lower head 34 of which is tted in a recess 35 in the base I5 and is adapted to coact with the bifurcated outer end 36 of the leaf spring 25, while its upper threaded end extends upwardly some distance above the nut 32; a cam 31 secured to a shaft 38 journalled in a socket 39 formed in the frame member II and having an external manipulating handle 40; an auxiliary U-shaped toggle lever 4| having side arms coacting with rear fulcrum notches 42 in the side walls I2 so as to swing therebetween, and also having lower lugs 43 cooperable with the bottom or the frame member to limit the downward'swing; a toggle actuating tension spring 44 connecting the central portions of the toggle levers 26, 4l to swing the same from one position to the other with a snap action; a set of movable switch contact carrier bars 45 slidable in upper and lower iixed insulation plates 46, 41 respectively, and each having a rear lower notch 46 with which the toggle lever 4I is cooperable; a transverse plate 49 loosely suspended from the medial portion of each carrier bar 45 and providing a support for a pair of movable contacts 56; a compression spring 5| embracing each bar 45 between the adjacent plates 41, 49; xed contacts 52 secured to the upper plate 46 and each having a terminal attaching screw 53 associated therewith; a ash guard 54 secured to the rear edges of the frame flanges I3 by a clip 55; an assembly plate 56 coacting with the frame member II beneath the lower insulation plate 41; and a removable cupshaped cover 51 coacting with the casing I5 and being detachably secured thereto by a clamping nut 58 coacting with the upper end of the threaded bolt 33.

Practically all of the important parts of the improved switch mechanism may be formed of sheet material with the aid of punchesr and dies,

or of standard stock, and the casing I5 maybe provided with suitable openings for the electrical connections associated with the terminal screws 53. While the general assemblage and operation of the improved switch are quite similar to those of the switch shown in prior Patent No. 2,193,127, the improved mechanism involves simplified instrumentalities for assembling and for maintaining the motion transmitting element or disk 23 in place; simpler and more eiective means comprising the assembly plate 56 for retaining the toggle in place and the frame in assembled condition; and improved means for effecting rapid and accurate adjustment of the toggle throw in order to insure most eflicient and sensitive operation.

Referring to Figs. 1, 2, 3 and 4, it is to be noted that one end of the flexible leaf spring 25 is riveted or otherwise rigidly attached to the center of the disk 23, while the opposite bifurcated end thereof is rmly clamped between the bolt head 34 and the recessed portion 35 of the frame base I6 within which the bolt head is snugly conned. In order to prevent the spring 25 from sliding away from the bolt 33 and thereby shifting the fulcrum projections 24 of the disk 23, the bifurcated spring end 36 is preferably provided with integral anges or projections 56 which snugly engage the bolt head 34 when the structure is assembled. The main spring 35 which embraces the bolt 33 and coacts with the lever 26 and nut 32, serves to normally hold the leaf spring 25 clamped in position, but the disk 23 and spring 25 may be readily released and removed from the switch assembly by merely compressing the spring 36 sufficiently to permit the projections 59 to be withdrawn forwardly over the top of the bolt head 34. The leaf spring 25 should be stii enough to normally maintain the side projections 24 of the disk 23 in proper position and in snug coaction with the sockets 26 of the toggle lever 26 at all times, and the use of such an external spring obviates obstructions within the fluid chamber 2| and permits `free flexing of the diaphragm |'1 under all conditions of operation.

Referring to Figs. 1, 2, 3 and 5, the improved assembly plate 56 for retaining the toggle and frame properly assembled, is formed of stii sheet metal and has the opposite sides of its front portion provided with notches 6I) rmly engaging the opposite sides of the front frame wall I4, while its rear portion is provided with integral depending lugs 6| which normally extend downwardly over the notches 42 in the rear portions of the frame walls I2 to prevent the toggle lever 4| from becoming displaced. The assembly plate 56 is moreover provided with integral upper op-r posite side lugs 62 which coact with the bottom of the lower insulation plate 41, and the plate 56 is thus heldrmly against the ledges of the frame member II formed between the side walls I2 and flanges I3. It will thus be noted that the assembly plate 56 not only retains the toggle lever 4| in proper position, but also strengthens the upper frame member |I by rmly retaining vthe front wall I4 thereof in upright position.

Again referring to Figs. 1, 2, 3 and 5, while the main spring 33 provides means for varying'the pressure at which the switch will act, it is also desirable to provide means for varying the pressure range of action, and for this purpose an adjustable screw 63 which coacts -with the front frame wall I4 is provided. while the swinging forward end of the auxiliary toggle lever 4 I has `heretofore been causedto coaot directlywith the enlarged head 63v of the screw 62, it has been 2,307,265 yfound desirable to increase the area of coaction,

and astop plate 64 of increased area has therefore .been applied directly beneath .the screw head 63'. This stop plate 64 is forced upwardly against the screw head 63' by a spring 65 embracing the screw 62 and coacting with the wall I4, and the screw 63 is snugly secured to the wall Id and is frictionally retained in various positions of adjustment, see Fig. 5.

During normal operation of the improved switch mechanism, Iwhen the cam actuating handle 40 is in upright position, the switch will be open and the cam 31 will be effective to hold the contacts 50, 52 open, by virtue of its coaction with the toggle lever 26. During such positioning of the switch the leaf spring 30 will function to retain the projections 24 of the disk 23 in engagement with the notches or sockets 23 of the main toggle lever 26, and the disk 23 canno-t become displaced from central position even if the switch assemblage is disposed on its side. When the cam 3l is positioned as in Figs. 1 and 2, the adjust-ing nut 32 may be manipulated to predetermine the pressure at which the switch will operate, and after the spring has been thus adjusted, reduction in pressure within the chamber 2| will cause the toggle. levers to throw over center in one direction, whereas increase in such fluid pressure will cause the toggle levers to throw over center in the opposite direction. Such actuation of the toggle levers is caused by the toggle spring 44 connecting the levers 28, 4l. rThe increase in pressure within the chamber 2| beyond a predetermined amount, will cause the switch to be open, whereas a decrease in said pressure below a certain amount will cause the switch to close. The actuation of the contacts is effected with a snap action in an obvious manner, and it will be apparent that the action of the switch when the cam 31 is inactive, is entirely automatic and the range of action can be quickly adjusted by manipulation of the adjusting screw 63.

From the foregoing detailed description it will be apparent that the present invention provides three major improvements over the prior switch assembly of the p-atent herein identified. The improved disk 23 and leaf spring 25 insures proper maintenance of the motion transmitting element interposed between the diaphragm I'l and lever 25, in desired position, while permitting convenient insertion and removal of the motion transmitting element. This improved struc ture moreover prevents clogging and obstruction of the pressure chamber 2l with unnecessary and undesirable parts, and the leaf spring 25 can be manufactured and applied at minimum expense. The improved assembly plate 56 obviously reinforces the entire frame structure and also maintains the toggles in proper operating position at all times; and the improved stop plate 64 which is associated with the adjusting screw 63, also materially enhances the efficiency of operation of the switch. The entire switch assemblage can be readily constructed and assembled or dismantled, at minimum cost and with minimum effort, and has proven highly successful in actual commercial use.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of operation, herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

It is claimed:

1. In combination, a frame having relatively 75 Vmovable contacts associatedtherewith, a lever operable to relatively move said contacts, a fluid pressure actuated diaphragm, a motion transmitting element interposed between said lever and said diaphragm, said element having nat surface contact with said diaphragm and knifeedge coaction with said lever, and a leaf spring for constantly urging said element against said lever, said leaf spring having one end secured to said element and its opposite end secured to said frame.

2. In combination, a frame having relatively movable contacts associated therewith, a lever operable to relatively move said contacts, a fluid pressure actuated diaphragm, a motion transmitting element interposed between said lever and said diaphragm, said element having flat surface contact with said diaphragm and knifeedge coaction with said lever, and a leaf spring for constantly urging said element against said lever, said leaf spring having one end rigidly attached to said element and its opposite end detachably secured to said frame.

3. In combination, a frame having relatively movable contacts associated therewith, a lever for relatively moving said contacts and being swingably suspended from said frame, a fluid pressure actuated diaphragm secured to said frame, a one piece motion transmitting element interposed directly between said lever and said diaphragm, said element having a disk in surface engagement with said diaphragm and an integral projection in pivotal coaction with said lever, and a leaf spring connecting said disk and said frame to constantly urge said disk projection into engagement with said lever.

4. In combination, a frame having relatively movable contacts associated therewith, a lever for relatively moving said contacts and being swingably suspended from said frame, a liuid pressure actuated diaphragm secured to said frame, a one piece motion transmitting element interposed directly between said lever and said diaphragm, said element having a disk in surface engagement with said diaphragm and an integral projection in pivotal coaction with Said lever, and a leaf spring having one end rigidly attached to said disk and its opposite end detachably secured to said frame, said spring being biased to constantly urge said disk projection against said lever.

5. In combination, a frame, a lever swingably suspended from said frame, a diaphragm associated with said frame laterally of said lever, a

.' rigid motion transmitting element interposed directly between said diaphragm and said lever, said element having a disk engaging said diaphragm and an integral projection in pivotal coaction with said lever, and a leaf spring connecting said disk with said frame.

6. In combination, a frame, a lever swingably suspended from said frame, a diaphragm associated with said frame laterally of said lever, a rigid motion transmitting element interposed directly between said diaphragm and said lever, said element having a disk engaging said dia.- phragm and an integral projection in pivotal coaction with said lever, and a leaf spring connecting said disk with said frame, said leaf spring being formed to constantly urge said disk toward said lever and having one end detachably connected to the adjacent structure.

7. In combination, a frame, a lever swingably suspended from said frame, a diaphragm spaced laterally from said lever, a motion transmitting said lever, a leaf spring connecting said element 2 with said frame, a bolt coacting with said frame through an end of said leaf spring, and a coil spring coacting with said lever and reacting against said bo-lt to exert a clamping effect upon said leaf spring end.

9. In combination, a frame, a toggle lever having one end pivotally suspended from said frame, a fluid pressure lexed diaphragm spaced laterally iromthe medial portion of said lever, a rigid motion-transmitting element interposed directly between said diaphragm and said medial lever portion, a leaf spring connecting said element and said frame, a bolt coacting with said frame through one end o-i said leaf spring, a coil spring embracing said bolt and coacting with the opposite end of said lever, and adjustable means carried by said bolt and against which said coil spring reacts.

l0. In combination, a frame, a toggle lever having one end pivotally suspended from said frame,k

a fluid pressure flexed diaphragm spaced laterally from the medial portion of said lever, a rigid motion transmitting element interposed directly between said diaphragm and said medial lever portion, a leaf spring having one end rigidly attached to said element and having an opposite bifurcated end coacting with said frame, a bolt having a head coacting with said frame through said bifurcated spring end and extending through said lever, a coil spring embracing said bolt and coacting with the opposite swinging end of said lever, and a nut adjustable along said bolt and against which said coil spring reacts t0 clamp said leaf spring in place.

11. In combination, a frame having opposite side walls formed integral with a base portion and also having an integral front Wall extending upwardly from said base portion and spanning the space between said side walls, a lever swingably suspended in notches at the rear edges of said side walls, and a separate assembly plate secured to said frame and having front portions interlocking with the upper end of said front wall and rear portions providing closures for said notches.

12. In combination, a one-piece frame member having a base and integral upstanding side walls and a front wall spanning the space between said side walls, each of said side walls having an offset portion at its upper end and also having a pivot notch in the rear edge thereof, a lever having pivot portions disposed within said notches, and a separate assembly plate resting upon said off-set portions and having integral front portions interlockable with said front wall and other integral portions providing closures for said\ notches. i,

13. In combination, a one-piece frame member having a base and integral upstanding side walls and a front wall spanning the space between said side walls, each of said side Walls having an oirset portion at its upper end and also having a pivot notch in the rear edge thereof, a lever having pivot portions disposed within said notches, and a single separate assembly plate coacting with said .off-set portions and having front notches coacting with the upper free end of said front wall and integral rear lugs spanning said pivot notches.

14. In combination, a one-piece sheet-metal frame member having a base and integral upstanding side Walls and a front wall spanning the space between said side walls, each of said side walls having an oiT-set portion at its upper end and .also having a pivot notch in the rear edge thereof, a lever having pivot portions disposed within said notches, and a single separate assembly plate coacting with said off-set portions and having front notches interlocking with the upper free end of said front wall and integral rear depending lugs spanning said pivot notches.

15. In combination, a frame having relatively movable contacts associated therewith, a lever for relatively moving said contacts and being swingably suspended from said frame, a iiuid `pressure actuated diaphragm secured to said frame, a one piece motion transmitting element interposed directly between said lever and said diaphragm, said element having a disk in surface engagement with said diaphragm and an integral projection in pivotal coaction with said lever, and elongated resilient means having one end rigidly attached to said disk and its opposite end detachably secured to said frame, said resilient means being biased to constantly urge said disk projection against said lever.

16. In combination, a frame having relatively movable contacts associated therewith, a lever operable to relatively move said contacts, a fluid pressure actuated diaphragm, a motion transmitting element interposed between said lever and said diaphragm, said element having at surface contact with said diaphragm and knife-edge coaction with said lever, and spring means for constantly urging said element against said lever, said spring means having one portion secured to said element and another portion secured to said frame.

GILBERT H. HANSEN. 

